Answer:
A. when the mass has a displacement of zero
Explanation:
The velocity of a mass on a spring can be calculated by using the law of conservation of energy. In fact, the total energy of the mass-spring system is equal to the sum of the elastic potential energy (U) of the spring and the kinetic energy (K) of the mass:
where
k is the spring constant
x is the displacement of the mass with respect to the equilibrium position of the spring
m is the mass
v is the velocity of the mass
Since the total energy E must remain constant, we can notice the following:
- When the displacement is zero (x=0), the velocity must be maximum, because U=0 so K is maximum
- When the displacement is maximum, the velocity must be minimum (zero), because U is maximum and K=0
Based on these observations, we can conclude that the velocity of the mass is at its maximum value when the displacement is zero, so the correct option is A.
Answer
Correct answers are 1.an increase or decrease in pressure 2.an increase or decrease in energy
Explanation
All existing matter can undergo phase change it means they may transform from one state to another. phase change of a matter may occur due to change in energy and change in pressures.
for example there is an ice cube which is a solid and if we want to change it phase into liquid water for that purpose we have to supply some energy to ice cube it means we have to give some heat to ice cube. After supplying heat energy to the ice it will turn into water it means there is phase change from solid to liquid due to supplying the heat. Similarly we can change the liquid water into solid ice cube by taking heat energy(reducing temperature) from the liquid water .
In some cases the matter doesn't want to undergo phase transformation. For example, oxygen will solidify at -361.8 degrees Fahrenheit at standard pressure.But , it can change to solid state at warmer temperatures when the pressure is increased.
Answer:
Cannot be determined from the given information
Explanation:
Given the following data;
Velocity = 24 m/s
Period = 3 seconds
To find the amplitude of the wave;
Mathematically, the amplitude of a wave is given by the formula;
x = Asin(ωt + ϕ)
Where;
x is displacement of the wave measured in meters.
A is the amplitude.
ω is the angular frequency measured in rad/s.
t is the time period measured in seconds.
ϕ is the phase angle.
Hence, the information provided in this exercise isn't sufficient to find the amplitude of the waveform.
However, the given parameters can be used to calculate the frequency and wavelength of the wave.
A "screen" or even just a set of parallel bars are highly reflective to electromagnetic waves as long as the open spaces are small compared to the wavelengths.
"Grid" dishes work fine ... with less weight and less wind resistance ... for frequencies below about 3 GHz. (Wavelengths of at least 10 cm.)
(I even worked on a microwave system in South America where huge grid dishes were used on a 90-mile link.)
Answer: a) 0.04kW = 40W
b) 0.05
Explanation:
A)
Thermal efficiency of the power cycle = Input / output
Input = 10 kW + 14,400 kJ/min = 10 kW + 14,400 kJ/(60s) = 10 kW + 14,400/60 kW.
Output = 10 kW
Thermal Efficiency = Output / Input = 10kW / 250kW = 0.04KW = 40W
B)
Maximum Thermal Efficiency of the power cycle = 1 - T1/T2
Where T1 = 285kelvin
And T2 = 300kelvin
Maximum Thermal Efficiency = 1 - T1/T2 = 1 - 285/300 = 0.05
